package com.vast.system.utils;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.auth0.jwt.interfaces.DecodedJWT;

import java.util.Date;

/**
 * @author zhaohao
 * @since 2018-10-23
 */
public class JWTUtil {

	 // 过期时间一天
    private static final long EXPIRE_TIME = 60 * 60 * 1000*24;

    /**
     * 校验token是否正确
     *
     * @param token  密钥
     * @param secret 用户的密码
     * @return 是否正确
     */
    public static boolean verify(String token, String userId, String secret) throws JWTVerificationException{
            Algorithm algorithm = Algorithm.HMAC256(secret);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withClaim("userId", userId)
                    .build();
            DecodedJWT jwt = verifier.verify(token);
            return true;
    }

    /**
     * 获得token中的信息无需secret解密也能获得
     *
     * @return token中包含的用户名
     */
    public static String getUserId(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("userId").asString();
        } catch (JWTDecodeException e) {
            return null;
        }
    }

    /**
     * 生成签名,5min后过期
     *
     * @param userId 用户名
     * @param secret   用户的密码
     * @return 加密的token
     */
    public static String sign(String userId, String secret) {
        Date date = new Date(System.currentTimeMillis() + EXPIRE_TIME);
		Algorithm algorithm = Algorithm.HMAC256(secret);
		// 附带username信息
		return JWT.create()
		        .withClaim("userId", userId)
		        .withExpiresAt(date)
		        .sign(algorithm);
    }

    /**
     * 生成token
     * @param userId
     * @param secret
     * @param date token过期时间
     * @return
     */
    public static String sign(String userId, String secret, Date date) {
        Algorithm algorithm = Algorithm.HMAC256(secret);
        // 附带username信息
        return JWT.create()
                .withClaim("userId", userId)
                .withExpiresAt(date)
                .sign(algorithm);
    }
}
